The Medicare 8-minute rule is the CMS method for converting direct, one-on-one therapy minutes into billable 15-minute units under Medicare Part B. A provider needs at least 8 minutes to bill one unit. When several timed codes are delivered on the same day, Medicare adds all timed minutes together, determines the total units allowed, and assigns those units to the services that took the most time.
Therapy notes rarely divide into perfect 15-minute blocks. A patient might receive 33 minutes of therapeutic exercise and 7 minutes of manual therapy, and the biller still has to decide how many units to report and which codes to use. Getting it wrong can leave earned revenue unclaimed or trigger an audit for excessive units. Specialty Medical Billing Services can help therapy practices maintain accurate coding, appropriate unit allocation, and compliant claim submissions. This guide explains the rule as CMS defines it, demonstrates the calculations through worked examples, and covers the documentation, modifiers, and payer differences that determine whether a claim withstands review.
What Is the Medicare 8-Minute Rule?
Many therapy CPT codes are defined as “each 15 minutes.” To report them, Medicare Part B follows Section 20.2 of Chapter 5 in the Medicare Claims Processing Manual (Pub. 100-04). It directs providers to bill one unit when treatment lasts at least 8 minutes, and not to bill a lone timed service that lasts fewer than 8 minutes. Eight is the midpoint: the point where the clinician has delivered more than half of a 15-minute unit.
The rule covers Part B outpatient therapy, including physical therapy, occupational therapy, and speech-language pathology, in settings such as private practices, rehabilitation agencies, hospital outpatient departments, and CORFs. Therapists inside orthopedic and sports medicine groups, which often rely on specialized orthopedic billing and sports medicine billing support, apply it every day. Only direct, one-on-one time counts, meaning skilled treatment the clinician personally delivers. Documentation, setup, waiting, and unattended modalities do not add timed minutes.
8-Minute Rule Chart: Minutes to Billable Units
Add up every timed minute delivered on the date of service, then read the allowed units from the chart below, which reflects CMS Pub. 100-04, Chapter 5, Section 20.2.
| Billable units | Total timed minutes |
| 1 unit | 8 to 22 minutes |
| 2 units | 23 to 37 minutes |
| 3 units | 38 to 52 minutes |
| 4 units | 53 to 67 minutes |
| 5 units | 68 to 82 minutes |
| 6 units | 83 to 97 minutes |
| 7 units | 98 to 112 minutes |
| 8 units | 113 to 127 minutes |
Beyond 8 units, each additional unit adds another 15-minute range, and fewer than 8 total timed minutes supports no timed unit. For a quick calculator-style shortcut, add 7 to the total timed minutes, divide by 15, and drop the decimal. For 40 minutes, (40 + 7) ÷ 15 = 3.13, so 3 units.
Timed vs. Untimed CPT Codes
The rule applies only to timed codes, whose descriptors include a time increment such as “each 15 minutes.” Untimed, or service-based, codes are reported once per session regardless of duration, and their minutes never count toward timed units.
| Code | Service | Type |
| 97110 | Therapeutic exercise | Timed |
| 97112 | Neuromuscular reeducation | Timed |
| 97116 | Gait training | Timed |
| 97140 | Manual therapy | Timed |
| 97530 | Therapeutic activities | Timed |
| 97535 | Self-care and home management training | Timed |
| 97032 | Electrical stimulation, attended | Timed |
| 97035 | Ultrasound | Timed |
| 97113 / 97124 / 97750 | Aquatic therapy / massage / physical performance test | Timed |
| 97161 to 97168 | PT and OT evaluations and re-evaluations | Untimed |
| G0283 (Medicare) / 97014 | Unattended electrical stimulation | Untimed |
| 97012 / 97150 | Mechanical traction / group therapy | Untimed |
Medicare requires G0283 for unattended electrical stimulation, while many commercial payers still accept 97014. Evaluation minutes stay out of the unit calculation, but they do count toward total treatment time in the note.
How to Calculate Units Under the 8-Minute Rule
Medicare uses the total time method. Follow these steps for each visit, as part of your wider medical billing process:
- Total the minutes of all timed services delivered that day. Exclude evaluations and untimed codes.
- Find the total units allowed for that number of minutes on the chart.
- Give each code one unit for every full 15 minutes it received.
- Assign any remaining units to the codes with the most leftover minutes. If the leftovers are equal, choose either code.
The total sets the ceiling. You can never bill more timed units than the combined minutes support, no matter how many services were performed.
8-Minute Rule Examples: Worked Calculations
These scenarios follow CMS and Medicare contractor examples and show how the same rule behaves with one code, several codes, and mixed services.
| Scenario | Timed minutes | Units | How to bill |
| 97110 for 18 minutes | 18 | 1 | 1 unit of 97110 |
| 97110 for 25 minutes | 25 | 2 | 2 units of 97110 |
| 97530 for 55 minutes | 55 | 4 | 4 units of 97530 |
| 97110 for 33 min + 97140 for 7 min | 40 | 3 | 2 units 97110, 1 unit 97140 |
| 97110 for 25 min + 97140 for 20 min | 45 | 3 | 2 units 97110, 1 unit 97140 |
| 97112 for 20 min + 97110 for 20 min | 40 | 3 | Either code gets 2 units, the other gets 1 |
| 97140, 97112, 97110 for 7 min each | 21 | 1 | 1 unit on one code of your choice |
| Four services at 8 min each | 32 | 2 | 2 units, not 4 |
Why 7 Minutes Can Still Earn a Unit
Many summaries say every billed code needs its own 8 minutes. Under Medicare, that is not correct. In the 33-minute 97110 and 7-minute 97140 scenario, 40 total minutes support three units. Exercise earns two full units with 3 minutes left over, and manual therapy has 7, the larger remainder, so it receives the third unit. The combined total, not the individual code, controls eligibility.
Why Four 8-Minute Services Equal Two Units
Each service passes 8 minutes on its own, yet 32 combined minutes fall in the 23 to 37 range, so only two units are allowed. This is the most common pooling error in Medicare therapy billing.
When Timed and Untimed Services Mix
A visit with 30 minutes of manual therapy and 20 minutes of mechanical traction (97012) supports two units of 97140 and one unit of 97012. Total treatment time is 50 minutes, but only the 30 timed minutes drive the unit calculation.
Documentation Requirements That Support Every Unit
Under the Medicare Benefit Policy Manual (Pub. 100-02), Chapter 15, Section 220.3, each treatment note must state the total timed code treatment minutes and the total treatment time in minutes, with total treatment time covering both timed and untimed services. CMS does not require separate minutes for every intervention, but the note must describe the skilled service behind each code billed, and some payers and contractors expect minutes by code. Recording start and stop times, or minutes per service, is the safest habit.
Noridian’s JE Part B guidance adds that billing rests solely on total timed code minutes, while the expectation remains that each unit averages 15 minutes of direct treatment. Notes must also sit inside a certified plan of care that is recertified at least every 90 days, with progress reports at least once every 10 treatment days. Identical round-number minutes on every visit invite questions because they look estimated rather than measured. These requirements flow from medical billing regulations and Section 1862(a)(1)(A) of the Social Security Act, which limits payment to services that are reasonable and necessary.
Modifiers and Payment Rules That Interact With Units
GP, GO, and GN
Outpatient therapy lines carry a modifier identifying the discipline of the plan of care: GP for physical therapy, GO for occupational therapy, and GN for speech-language pathology.
CQ and CO
Services furnished in whole or in part by a physical therapist assistant carry CQ, and those furnished by an occupational therapy assistant carry CO, with payment at 85 percent of the fee schedule amount. CMS applies a de minimis standard, so the modifier is not needed when the assistant furnishes 10 percent or less of a service. When one final unit remains and the therapist personally furnishes at least 8 minutes, that unit is billed without CQ or CO.
KX Modifier Threshold
For CY 2026, the KX threshold is $2,480 for PT and speech-language pathology services combined, with a separate $2,480 threshold for occupational therapy. Above it, claims must carry KX to confirm medical necessity or they are denied. The targeted medical review threshold remains $3,000. Inflated units push a patient toward these thresholds faster, so accurate counts matter beyond a single claim.
Multiple Procedure Payment Reduction
Medicare reduces the practice expense portion of payment by 50 percent for the second and subsequent “always therapy” units delivered the same day, so extra units do not add full payment. Patients also owe the Part B coinsurance, which practices track through PR-2 coinsurance adjustments on remittances.
Common 8-Minute Rule Mistakes and How to Avoid Them
Most unit errors fall into a handful of patterns, many of which also appear among common medical billing mistakes across specialties.
| Mistake | Why it matters | Fix |
| Testing 8 minutes per code on Medicare claims | Overstates units (10 + 10 minutes gives 2 instead of 1) | Pool all timed minutes first |
| Counting evaluation or untimed minutes | Inflates the unit ceiling | Count timed minutes only |
| One unit per code that reached 8 minutes | Exceeds the total allowed | Read the chart on combined minutes |
| Using total visit time | Overbills the timed units | Separate timed from total treatment time |
| Billing 97014 to Medicare | Wrong code for unattended e-stim | Use G0283 |
| Estimated or cloned time entries | Fails medical review | Record actual minutes or start and stop times |
| Missing CQ, CO, or KX | Underpayment or denial | Build claim edits and threshold alerts |
| Assuming all payers use the Medicare method | Under- or overbilled claims | Verify each payer policy |
Does the 8-Minute Rule Apply to Commercial Payers?
Not automatically. Medicare and many federal programs require the total time method, but many commercial insurers follow the AMA’s CPT time approach, often called the Rule of Eights, which tests each code separately. With 10 minutes of 97110 and 10 minutes of 97140, Medicare allows one unit because the pooled total is 20 minutes, while the AMA approach allows one unit per code, or two. Medicare Advantage, Medicaid, and commercial plans can set their own policies, so confirm each contract’s rule during payer credentialing and in the provider manual. Our companion guide, Medicare 8-Minute Rule vs. AMA Rule of Eights, compares both methods in detail.
How Practices Can Stay Compliant and Protect Revenue
Unit errors cut both ways. Undercounting leaves earned payment unclaimed, while overcounting creates repayment risk. CMS’s approved Recovery Audit topic on excessive units for untimed therapy codes shows that auditors look closely at unit counts. Practical safeguards include building the chart and the total-time ceiling into the EHR, training clinicians to record timed minutes and total treatment time at the point of care, and reviewing a sample of notes each month.
A periodic medical billing audit catches patterns before payers do, and AI in medical billing tools can flag mismatches between minutes and units before a claim goes out. Clean units also support claim denial reduction and steadier cash flow across your revenue cycle management workflow. Proactive Healthcare Services helps therapy practices apply these rules consistently through specialized physical therapy medical billing, unit-accuracy audits, and denial follow-up, so your team can focus on patient care instead of recalculating minutes.
Frequently Asked Questions
How many minutes do you need to bill one unit under the 8-minute rule?
You need at least 8 minutes of direct, one-on-one treatment. One unit covers 8 to 22 total timed minutes, and each further unit adds another 15-minute range.
How many units can you bill for 60 minutes?
Sixty timed minutes fall in the 53 to 67 range, so you can bill 4 units. If part of the hour was untimed, such as an evaluation, only the timed minutes count.
Can you bill a service that lasted only 7 minutes?
Not on its own. In a multi-code session, it can receive a unit if the combined timed minutes support another unit and it has the largest remaining minutes, as with 33 minutes of 97110 plus 7 minutes of 97140.
Does the 8-minute rule include evaluation time?
No. Evaluations and re-evaluations are untimed codes billed once per session. Their minutes appear in total treatment time but never in the timed unit calculation.
Is the 8-minute rule the same as the Rule of Eights?
No. The Medicare rule pools minutes across all timed codes, while the AMA Rule of Eights applies the 8-minute test to each code separately, which can produce a different unit count.
Does the 8-minute rule apply to Medicare Advantage plans?
It depends on the plan. Many follow Medicare payment methods, but each plan sets its own policy, so confirm the unit calculation method in the contract or provider manual.
Key Takeaways
The Medicare 8-minute rule comes down to three habits: pool the timed minutes, read the chart, and document the totals. Apply the same discipline to modifiers, thresholds, and payer policies, and your claims will hold up under review while still capturing every unit you earned.
Simplify Therapy Billing with Proactive Healthcare Services
Accurate application of the Medicare 8-minute rule is essential for reducing billing errors, preventing avoidable claim denials, and protecting your practice’s revenue. Proactive Healthcare Services helps physical therapy, occupational therapy, and speech-language pathology practices improve billing accuracy through specialized medical billing, unit-accuracy audits, and denial management support.
Let our experienced team help you maintain accurate documentation, apply payer-specific billing rules, and streamline your revenue cycle while you focus on delivering quality patient care.
Ready to improve your therapy billing process?
Contact Proactive Healthcare Services today to discuss how our medical billing solutions can support your practice.
Call: +1 888-586-8881
Email: info@phcss.com
